When photographing a subject having a large depth by an imaging apparatus such as a digital camera, or the like, so-called erroneous focusing, that is, focusing on a not-desired position occurs due to a performance limit of algorithm, hardware, or the like so that photographing a desired part of the subject in a focused state is difficult, as a result. In this case, in order to overcome the erroneous focusing problem, focus bracket photographing for continuously photographing a subject while sequentially changing the focusing position to obtain a plurality of photographed images at once is used. The focus bracket photographing is, in general, performed by changing the focusing position forward and backward to photograph about three times and therefore it is difficult to overcome the erroneous focusing problem.
Furthermore, it has been required by photographers, who do not decide which subject is to be focused, to select the best one from a plurality of photographed images obtained by changing the photographing positions after comparing and investigating the plurality of photographed images. For example, when photographing, for example, a flower under optical conditions in a telemacro mode of a small depth of field, in some cases, it cannot be decided before photographing whether focusing on a petal of the flower at a near side or a pistil or stamen of the flower and therefore favorable one to photograph a favorable one.
For example, Japanese Patent Application Publication No. 2004-135029 discloses a camera performing a focus bracket photographing by changing the focusing position at one operation of pushing down a release button.
Japanese Patent Application Publication No. 2002-277725 does not disclose the focus bracket photographing but discloses focus control process including dividing an image into a plurality of blocks, controlling exposure in each block such that brightness in each block is in a predetermined level, generating focus evaluation value of each block, and then generating new focus evaluation value based on the focus evaluation values of the blocks within a predetermined focus range.
However, in the conventional focus bracket photographing, there are the following problems:    (1) an unnecessary image where no subject is focused on within the image is photographed; and    (2) it is difficult for a user to confirm which part within each of the plurality of photographed images is focused on.